/*
 * Copyright (c) 2001 Matthew Feldt. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided the copyright notice above is
 * retained.
 *
 * THIS SOFTWARE IS PROVIDED ''AS IS'' AND WITHOUT ANY EXPRESSED OR
 * IMPLIED WARRANTIES.
 */

/**
 * BinaryProperties.java
 *
 * Java Examples In A Nutshell Copyright (c) 2000 David Flanagan
 * Exercise 9-1:
 * The java.util.Properties class is essentially a hashtable that maps string
 * keys to string values. It defines store() and load() methods that save and
 * load its contents to and from a byte stream. These methods save the Properties
 * object in a human-readable text format despite the fact that they use
 * byte streams. Properties inherits the Serializable interface from its super-
 * class, java.util.Hashtable. Define a subclass of Properties that implements
 * storeBinary() and loadBinary() methods that use object serialization to
 * save and load the contents of the Properties object in binary form. You
 * may also want to use java.util.zip.GZIPOutputStream and java.util.zip.GZIP-
 * InputStream in your methods to make the binary format particularly compact.
 * Use the serialver program to obtain a serialVersionUID value for your class.
 *
 * @author Matthew Feldt <developer@feldt.com>
 * @version 1.0, 05/27/2001 10:05
 */


package com.feldt.examples.serialization;
import java.io.*;
import java.util.*;
import java.util.zip.*;

/**
 * An extension of the java class Properties that implements compressed
 * binary serialization.
 */
class BinaryProperties extends Properties {
	/** serialVersionUID from $JAVA_HOME/bin/serialver. */
	static final long serialVersionUID = -626753475793321398L;

	/** Serialize Property object to File f. */
	public static void storeBinary(Properties p, File f) throws IOException {
		ObjectOutputStream out = new ObjectOutputStream(
			new GZIPOutputStream(new FileOutputStream(f)));
		out.writeObject(p);
		out.close();
	}

	/** Read Property object from serialization data in File f. */
	public static Properties loadBinary(File f)
			throws IOException, ClassNotFoundException {
		ObjectInputStream in = new ObjectInputStream(
			new GZIPInputStream(new FileInputStream(f)));
		return (Properties)in.readObject();
	}

	/** test class */
	static class Test {
		public static void main(String[] args) {
			final String FILE_NAME = "bp.out";
			BinaryProperties bp = new BinaryProperties();
			bp.setProperty("one", "first");
			bp.setProperty("two", "second");
			bp.setProperty("three", "third");

			try {
				bp.storeBinary(bp, new File(FILE_NAME)); // serialize Properties
				// read the serialized data in to a new object
				Properties copy =
					new BinaryProperties().loadBinary(new File(FILE_NAME));
				System.out.println(copy);
				if (copy.equals(bp)) System.out.println("Copies equal.");
			} catch(IOException e) {
				System.err.println(e.getMessage());
			} catch(ClassNotFoundException e) {
				System.err.println(e.getMessage());
			}
		}
	}
}